類指針引用

類的對象指針和二級指針

1 #include <iostream>
 2 
 3 class myclass
 4 {
 5 public:
 6     int x;
 7     int y;
 8 public:
 9     myclass(int, int);//構造函數
10     void printxy();
11 };
12 
13 myclass::myclass(int a, int b) :x(a), y(b)//構造函數
14 {
15 
16 }
17 
18 void myclass::printxy()
19 {
20     std::cout << x << " " << y << std::endl;
21 }
22 
23 void main()
24 {
25     myclass *p(new myclass(10, 9));//一級指針
26     
27     p->printxy();
28 
29     myclass class1(20, 1);
30 
31     myclass **pp = &p;//二級指針
32 
33     (*pp)->printxy();//一級指針
34     (**pp).printxy();//0級指針
35     
36     system("pause");
37 }      

1 #include <iostream>
 2 
 3 class myclass
 4 {
 5 public:
 6     int x;
 7     int y;
 8 public:
 9     myclass(int, int);//構造函數
10     void printxy();
11 };
12 
13 myclass::myclass(int a, int b) :x(a), y(b)//構造函數
14 {
15 
16 }
17 
18 void myclass::printxy()
19 {
20     std::cout << x << " " << y << std::endl;
21 }
22 
23 myclass class1(10, 11);
24 myclass class2(11, 12);
25 
26 void change1(myclass **pp)//二級指針
27 {
28     *pp = &class2;
29 }
30 
31 void change2(myclass * & p)//引用一個指針
32 {
33     p = &class1;
34 }
35 
36 void main()
37 {
38     myclass *p = &class1;
39 
40     p->printxy();
41 
42     change1(&p);
43 
44     p->printxy();
45 
46     change2(p);
47 
48     p->printxy();
49     
50     system("pause");
51 }